double-language learning的用法和樣例：
例句
- L1 transfer is a common phenomenon in learning a second language.
摘要在二語(yǔ)習得過(guò)程中，母語(yǔ)遷移是個(gè)普遍現象。 - During the past three decades, researchers have extensively studied the acquisition of temporality in second language acquisition.
摘要本文全面介紹了國外時(shí)體系統二語(yǔ)習得研究的主要方法和發(fā)現。
